Mining equipment, such as mining shovels, are a significant capital expenditure. It is important, therefore, to maximize operational time of this equipment. Mining shovels, for example, are operated almost constantly, as much as twenty-four hours a day, three hundred and sixty-five days a year. To minimize down time, it is therefore important that the equipment be suited to the environmental conditions in which the equipment operates.
The environment in which mining equipment is used, however, is extremely dirty, and includes both a significant amount of air borne dust and moisture. Because of these environmental conditions, hydraulic systems and components, which are particularly prone to contamination, are often avoided in mining shovel constructions. Hydraulic systems, however, can be very efficient, and are therefore also desirable in mining shovel applications. Accordingly, a need exists for a hydraulic system which is shielded from the operating environment, and which can therefore increase operational time and minimize the need for maintenance.